WO2020160084A1 - Lidar system including a transceiver array - Google Patents
Lidar system including a transceiver array Download PDFInfo
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- WO2020160084A1 WO2020160084A1 PCT/US2020/015572 US2020015572W WO2020160084A1 WO 2020160084 A1 WO2020160084 A1 WO 2020160084A1 US 2020015572 W US2020015572 W US 2020015572W WO 2020160084 A1 WO2020160084 A1 WO 2020160084A1
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- lens
- detectors
- light sources
- light
- platform
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- 238000000034 method Methods 0.000 claims description 33
- 230000003287 optical effect Effects 0.000 claims description 27
- 230000007246 mechanism Effects 0.000 claims description 9
- 230000005693 optoelectronics Effects 0.000 description 11
- 238000001514 detection method Methods 0.000 description 5
- 238000012856 packing Methods 0.000 description 5
- 238000003491 array Methods 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
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- 230000008901 benefit Effects 0.000 description 2
- 230000021615 conjugation Effects 0.000 description 2
- 238000003384 imaging method Methods 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000002310 reflectometry Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/497—Means for monitoring or calibrating
- G01S7/4972—Alignment of sensor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/02—Details
- G01J1/0295—Constructional arrangements for removing other types of optical noise or for performing calibration
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/42—Simultaneous measurement of distance and other co-ordinates
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/88—Lidar systems specially adapted for specific applications
- G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
- G01S17/894—3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/4808—Evaluating distance, position or velocity data
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4811—Constructional features, e.g. arrangements of optical elements common to transmitter and receiver
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4814—Constructional features, e.g. arrangements of optical elements of transmitters alone
- G01S7/4815—Constructional features, e.g. arrangements of optical elements of transmitters alone using multiple transmitters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4816—Constructional features, e.g. arrangements of optical elements of receivers alone
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4817—Constructional features, e.g. arrangements of optical elements relating to scanning
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/486—Receivers
- G01S7/4865—Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak
Definitions
- LiDAR sensors can be applied in autonomous vehicles, drones, robotics, security applications, and the like.
- LiDAR sensors may achieve high angular resolutions appropriate for such applications.
- LiDAR sensors may include laser sources for emitting laser beams, and detectors for detecting reflected laser beams.
- There is a need for improved LiDAR sensors that can be operated at relatively high laser powers and yet still meet eye- safety requirements.
- improved configurations of LiDAR components may facilitate easier optical alignments and afford other advantages.
- a LiDAR system includes a first lens having a first optical axis, a first set of light sources and a first set of detectors positioned substantially at a focal plane of the first lens, a second lens having a second optical axis substantially parallel to the first optical axis, and a second set of light sources and a second set of detectors positioned substantially at a focal plane of the second lens.
- Each respective detector of the second set of detectors is located at a respective detector position on the focal plane of the second lens that is optically conjugate with a respective position of a corresponding light source of the first set of light sources on the focal plane of the first lens, so that the respective detector of the second set of detectors detects a light beam that is emitted by the
- Each respective detector of the first set of detectors is located at a respective detector position on the focal plane of the first lens that is optically conjugate with a respective position of a corresponding light source of the second set of light sources on the focal plane of the second lens, so that the respective detector of the first set of detectors detects a light beam that is emitted by the corresponding light source of the second set of light sources and is reflected off of the one or more objects.
- a method of operating a LiDAR system includes a first lens, a second lens, a first set of light sources, a second set of light sources, a first set of detectors, and a second set of detectors.
- the method includes, at a first instant, emitting a first set of light pulses using the first set of light sources; and projecting, using the first lens, the first set of light pulses toward one or more objects.
- the first set of light pulses is reflected by the one or more objects.
- the method further includes focusing, using the second lens, the first set of light pulses reflected by the one or more objects onto the second set of detectors; and detecting, using the second set of detectors, the first set of light pulses focused by the second lens.
- the method further includes, at a second instant subsequent to the first instant, emitting a second set of light pulses using the second set of light sources; and projecting, using the second lens, the second set of light pulses toward the one or more objects.
- the second set of light pulses is reflected by the one or more objects.
- the method further includes focusing, using the first lens, the second set of light pulses reflected by the one or more objects onto the first set of detectors; and detecting, using the first set of detectors, the second set of light pulses focused by the first lens.
- a method of aligning a LiDAR system includes a first lens, a second lens, a first set of light sources, a second set of light sources, a first set of detectors, and a second set of detectors.
- the method includes arranging the first set of light sources and the first set of detectors as a first transceiver array positioned substantially at a focal plane of the first lens; arranging the second set of light sources and the second set of detectors as a second transceiver array positioned substantially at a focal plane of the second lens; emitting a first set of light beams using the first set of light sources; projecting, using the first lens, the first set of light beams toward a screen, thereby forming a first set of light spots on the screen; emitting a second set of light beams using the second set of light sources; projecting, using the second lens, the second set of light beams toward the screen, thereby forming a second set of light spots on the screen; and adjusting a position of the first lens relative to the first transceiver array, and a position of the second lens relative to the second transceiver array, until the first set of light spots and the second set of light spots form a predetermined pattern on the screen, such that each respective detector of the first set of
- each respective detector of the second set of detectors is optically conjugate with a corresponding light source of the first set of light sources.
- FIG. 1 illustrates schematically a LiDAR sensor for three-dimensional imaging according to some embodiments.
- FIG. 2 illustrates schematically an exemplary LiDAR system according to some embodiments.
- FIG. 3 illustrates schematically a scanning LiDAR system according to some embodiments.
- FIG. 4 shows schematically exemplary optical paths of light beams in the LiDAR system illustrated in FIG. 3.
- FIG. 5 illustrates schematically a scanning LiDAR system according to some embodiments.
- FIG. 6 shows schematically a configuration of the light sources and the detectors according to some embodiments.
- FIG. 7 shows an exemplary arrangement of two transceiver arrays in a LiDAR system according to some embodiments.
- FIG. 8 illustrates a schematic cross-sectional view of a scanning LiDAR system according to some embodiments.
- FIG. 9 is a simplified flowchart illustrating a method of operating a LiDAR system according to some embodiments.
- FIG. 10 is a simplified flowchart illustrating a method of aligning a LiDAR system according to some embodiments.
- Some LiDAR systems include a first lens for collimating or projecting outgoing laser beams emitted by laser sources, and a second lens for focusing return laser beams onto light detectors.
- the LiDAR systems may include an array of laser sources positioned behind the first lens, and a corresponding array of light detectors positioned behind the second lens.
- the operating powers of the laser sources may be limited by eye-safety requirements.
- the packing density of the laser sources and the detectors may be limited by the dimension of the larger device (including associated circuitry) between the laser source and the detector.
- a LiDAR system may include two lenses, and two transceiver arrays, each transceiver array being positioned behind each respective lens.
- Each transceiver array includes one or more laser sources and one or more light detectors.
- each lens functions as both as a transmitting lens for projecting light beams emitted by the one or more laser sources, and as a receiving lens for focusing return light beams onto the one or more light detectors.
- FIG. 1 illustrates schematically a LiDAR sensor 100 for three-dimensional imaging according to some embodiments.
- the LiDAR sensor 100 includes an emitting lens 130 and a receiving lens 140.
- the LiDAR sensor 100 includes a laser source 110a disposed
- the laser source 110a is operative to emit a laser pulse 120 from a respective emission location in the back focal plane of the emitting lens 130.
- the emitting lens 130 is configured to collimate and direct the laser pulse 120 toward an object 150 located in front of the LiDAR sensor 100. For a given emission location of the laser source 110a, the collimated laser pulse 120' is directed at a corresponding angle toward the object 150.
- a portion 122 of the collimated laser pulse 120' is reflected off of the object 150 toward the receiving lens 140.
- the receiving lens 140 is configured to focus the portion 122’ of the laser pulse reflected off of the object 150 onto a corresponding detection location in the focal plane of the receiving lens 140.
- the LiDAR sensor 100 further includes a detector 160a disposed substantially at the focal plane of the receiving lens 140.
- the detector 160a is configured to receive and detect the portion 122’ of the laser pulse 120 reflected off of the object at the corresponding detection location.
- the corresponding detection location of the detector 160a is optically conjugate with the respective emission location of the laser source 110a.
- the laser pulse 120 may be of a short duration, for example, 10 ns pulse width.
- the LiDAR sensor 100 further includes a processor 190 coupled to the laser source 110a and the detector 160a.
- the processor 190 is configured to determine a time of flight (TOF) of the laser pulse 120 from emission to detection. Since the laser pulse 120 travels at the speed of light, a distance between the LiDAR sensor 100 and the object 150 may be determined based on the determined time of flight.
- TOF time of flight
- One way of scanning the laser beam 120' across a FOV is to move the laser source 110a laterally relative to the emission lens 130 in the back focal plane of the emission lens 130.
- the laser source 110a may be raster scanned to a plurality of emission locations in the back focal plane of the emitting lens 130 as illustrated in FIG. 1.
- the laser source 110a may emit a plurality of laser pulses at the plurality of emission locations. Each laser pulse emitted at a respective emission location is collimated by the emitting lens 130 and directed at a respective angle toward the object 150, and impinges at a corresponding point on the surface of the object 150.
- the laser source 110a is raster scanned within a certain area in the back focal plane of the emitting lens 130, a corresponding object area on the object 150 is scanned.
- the detector 160a may be raster scanned to be positioned at a plurality of corresponding detection locations in the focal plane of the receiving lens 140, as illustrated in FIG. 1.
- the scanning of the detector 160a is typically performed synchronously with the scanning of the laser source 110a, so that the detector 160a and the laser source 110a are always optically conjugate with each other at any given time.
- the distance from the LiDAR sensor 100 to each corresponding point on the surface of the object 150 may be determined.
- the processor 190 is coupled with a position encoder that detects the position of the laser source 110a at each emission location. Based on the emission location, the angle of the collimated laser pulse 120' may be determined. The X-Y coordinate of the corresponding point on the surface of the object 150 may be determined based on the angle and the distance to the LiDAR sensor 100.
- a three-dimensional image of the object 150 may be constructed based on the measured distances from the LiDAR sensor 100 to various points on the surface of the object 150.
- the three-dimensional image may be represented as a point cloud, i.e., a set of X, Y, and Z coordinates of the points on the surface of the object 150.
- the intensity of the return laser pulse 122' is measured and used to adjust the power of subsequent laser pulses from the same emission point, in order to prevent saturation of the detector, improve eye-safety, or reduce overall power consumption.
- the power of the laser pulse may be varied by varying the duration of the laser pulse, the voltage or current applied to the laser, or the charge stored in a capacitor used to power the laser. In the latter case, the charge stored in the capacitor may be varied by varying the charging time, charging voltage, or charging current to the capacitor.
- the intensity may also be used to add another dimension to the image.
- the image may contain X, Y, and Z coordinates, as well as reflectivity (or brightness).
- the angular field of view (AFOV) of the LiDAR sensor 100 may be estimated based on the scanning range of the laser source 110a and the focal length of the emitting lens 130 as,
- the LiDAR sensor 100 may include multiple laser sources disposed as an array at the back focal plane of the emitting lens 130, so that a larger total AFOV may be achieved while keeping the scan range of each individual laser source relatively small.
- the LiDAR sensor 100 may include multiple detectors disposed as an array at the focal plane of the receiving lens 140, each detector being conjugate with a respective laser source.
- the LiDAR sensor 100 may include a second laser source 110b and a second detector 160b, as illustrated in FIG. 1.
- the LiDAR sensor 100 may include four laser sources and four detectors, or eight laser sources and eight detectors.
- the LiDAR sensor 100 may include 8 laser sources arranged as a 4x2 array and 8 detectors arranged as a 4x2 array, so that the LiDAR sensor 100 may have a wider AFOV in the horizontal direction than its AFOV in the vertical direction.
- the total AFOV of the LiDAR sensor 100 may range from about 5 degrees to about 15 degrees, or from about 15 degrees to about 45 degrees, or from about 45 degrees to about 120 degrees, depending on the focal length of the emitting lens, the scan range of each laser source, and the number of laser sources.
- the laser source 110a may be configured to emit laser pulses in the ultraviolet, visible, or near infrared wavelength ranges.
- the energy of each laser pulse may be in the order of microjoules, which is normally considered to be eye-safe for repetition rates in the KHz range.
- the detector 160a may comprise a silicon avalanche photodiode, a photomultiplier, a PIN diode, or other semiconductor sensors.
- the angular resolution may also depend on the size of the emission area of the laser source 110a and aberrations of the lenses 130 and 140.
- the angular resolution of the LiDAR sensor 100 may range from about 1 mrad to about 20 mrad (about 0.05-1.0 degrees), depending on the type of lenses.
- FIG. 2 illustrates schematically an exemplary LiDAR system 200.
- the LiDAR system 200 may include two lenses - an emission lens 230 and a receiving lens 240.
- Each of the emission lens 230 and the receiving lens 240 may be a compound lens that includes multiple lens elements.
- the emission lens 230 and the receiving lens 240 may be mounted in a lens mount 220.
- the lens mount 220 with the emission lens 230 and the receiving lens 240 attached thereto may be referred to herein as a lens assembly.
- the LiDAR system 200 may also include one or more light sources 210 (e.g., laser sources), and one or more detectors 260 (e.g., four light sources 210 and four detectors 260 as shown in FIG. 2).
- the light sources 210 may be mounted on an optoelectronic board 250 and are positioned behind the emission lens 230 (e.g., in the focal plane of the emission lens 230).
- the detectors 260 may be mounted on an optoelectronic board 250 and positioned behind the receiving lens 240 (e.g., in the focal plane of the receiving lens 240).
- the optoelectronic board 250 with the laser sources 210 and the detectors 260 mounted thereon may be referred to herein as an optoelectronic assembly.
- each respective light source 210a and a corresponding detector 260a are positioned on the optoelectronic board 250 such that the position of each respective light source 210a is optically conjugate with the position of the corresponding detector 260a. Therefore, a light beam emitted by a respective light source 210a may be projected or collimated by the emission lens 230, and reflected off of an object in front of the LiDAR system 200; and the reflected light beam may be focused by the receiving lens 240 onto the corresponding detector 260a.
- the lens assembly may be flexibly attached to the base 202 via a pair of flexures 270a and 270b as illustrated in FIG. 2.
- One end of each of the pair of flexures 270a and 270b is attached to the base 202, while the other end is attached to the lens assembly 220.
- the pair of flexures 270a and 270b may be coupled to an actuator 204 (also referred herein as a driving mechanism), such as a voice coil motor.
- the actuator 204 may be controlled by a controller 206 to cause the pair of flexures 270a and 270b to be deflected left or right as in a parallelogram, thus causing the lens assembly 220 to move left or right as indicated by the double-sided arrow in FIG. 2.
- the lateral movement of the emission lens 230 may cause the laser beams emitted by the laser sources 210 to be scanned across a FOV in front of the LiDAR system 200. As the entire lens assembly 220, including the emission lens 230 and the receiving lens 240, is moved as a single unit, the optical conjugate relationship between the laser sources 210 and the detectors 260 are maintained as the lens assembly 220 is scanned.
- FIG. 2 shows two rod-shaped flexures 270a and 270b for moving the lens assembly 220
- other flexure mechanisms or stages may be used.
- springs, air bearings, and the like may be used.
- the drive mechanism 204 may include a voice coil motor (VCM), a piezo-electric actuator, and the like.
- VCM voice coil motor
- the pair of flexures 270a and 270 b and drive mechanism 204 may be operated at or near its resonance frequency in order to minimize power requirements.
- the scanning may be achieved by other ways.
- scanning may be implemented using a rotating platform encompassing the emission lens 230, the receiving lens 240, the light sources 210, and the detectors 260.
- a rotating polygonal mirror, or one or more oscillating mirrors may be used.
- the LiDAR system 200 may include a plurality of light sources 210 and a plurality of detectors 260.
- the plurality of light sources 210 may be arranged as either a one- dimensional or a two-dimensional array (e.g., in the case of a two-dimensional array, there may be one or more rows offset from each other in the direction perpendicular to the paper).
- the plurality of detectors 260 may also be arranged as either a one-dimensional or a two-dimensional array.
- the optoelectronic board 250 as illustrated in FIG. 2 may have certain disadvantages.
- the permissible power of each light source 210 may be limited in order to ensure eye safety, since the light beams emitted by all of the light sources 210 may be concentrated spatially after being projected by the emission lens 230.
- the maximum packing density of the light sources 210 or the detectors 260 on the optoelectronic board 250 may be limited by the dimension of the larger device between the light source 210 and the detector 260.
- each detector 260 (including the associated circuitry) has a larger dimension than that of each light source 210, and that the plurality of detectors 260 are as closely packed as possible so that there is minimal space between adjacent detectors 260.
- the plurality of light sources 210 would need to be packed at the same density in order to maintain the conjugation relationships with the corresponding detectors 260, even though the light sources 210 are not as closely packed as possible.
- FIG. 3 illustrates schematically a scanning LiDAR system 300 according to some embodiments. Similar to the LiDAR system 200 illustrated in FIG. 2, the LiDAR system 300 also include two lenses - a first lens 330 and a second lens 340. The first lens 330 and the second lens 340 may be mounted in a lens mount 320. The first lens 330 has a first optical axis 332, and the second lens 340 has a second optical axis 342 substantially parallel to the first optical axis 332.
- the LiDAR system 300 further includes a plurality of light sources 310 and a plurality of detectors 360. The light sources 310 and the detectors 360 may be mounted on an optoelectronic board 350.
- a first set of light sources 310a and a first set of detectors 360a are positioned in the focal plane of the first lens 330
- a second set of light sources 310b and a second set of detectors 360b are positioned in the focal plane of the second lens 340.
- the first set of light sources 310a and the first set of detectors 360a behind the first lens 330 may be referred to as a first transceiver array.
- the a second set of light sources 310b and the second set of detectors 360b behind the second lens 340 may be referred to as a second transceiver array.
- each of the first lens 330 and the second lens 340 functions as both emission lens and receiving lens. Therefore, the first lens 330 and the second lens 340 may be referred to as transceiver lenses.
- Each respective detector 360b of the second set of detectors 360b is located at a respective detector position on the focal plane of the second lens 340 that is optically conjugate with a respective position of a corresponding light source 310a of the first set of light sources 310a on the focal plane of the first lens 330, so that the respective detector 360b of the second set of detectors 360b detects a light beam that is emitted by the corresponding light source 310a of the first set of light sources 310a and is reflected off of one or more objects (not shown in FIG. 3) in front of the first lens 330 and the second lens 340.
- each respective detector 360a of the first set of detectors 360a is located at a respective detector position on the focal plane of the first lens 330 that is optically conjugate with a respective position of a corresponding light source 310b of the second set of light sources 310b on the focal plane of the second lens 340, so that the respective detector 360a of the first set of detectors 360a detects a light beam that is emitted by the respective detector 360a of the first set of detectors 360a detects a light beam that is emitted by the
- FIG. 4 shows schematically exemplary optical paths of light beams in the LiDAR system 300 illustrated in FIG. 3.
- a light beam emitted by the light source 310a is projected by the first lens 330 toward an object 410 (e.g., a house), and is reflected by the object 410.
- the reflected light beam is received and focused by the second lens 340 onto the detector 360b.
- a light beam emitted by the light source 310b is projected by the second lens 340 toward the object 410, and is reflected by the object 410.
- each of the first lens 330 and the second lens 340 serves as both an emission lens and a receiving lens.
- the first lens 330 serves as an emission lens for the first set of light sources 360a, and as a receiving lens for the first set of detectors 360a.
- the second lens 340 serves as an emission lens for the second set of light sources 360b, and as a receiving lens for the second set of detectors 360b.
- the LiDAR system 300 may afford several advantageous. For example, if light beams projected by the two lenses 330 and 340 are spaced apart father than the aperture of a human eye, the light sources 310 can be operated at higher power levels and still meet the requirement for ensuring eye safety, because the light sources 310 are divided between two lenses 330 and 340 instead of all of them being behind one lens (e.g., as in the LiDAR system 200 illustrated in FIG. 2),
- the light sources 310 and the detectors 360 may be more densely packed on the optoelectronic board 350. As discussed above with reference to FIG. 2, with the arrangement of the light sources 210 and the detectors 260 in the LiDAR system 200, the maximum packing density is limited by the dimension of the larger device between the light source 210 and the detector 260. In contrast, in the LiDAR system 300 illustrated in FIG. 3, a higher packing density may be achieved by interspersing the light sources 310 and the detectors 360. Thus, the LiDAR system 300 may afford higher lateral spatial resolutions with a higher packing density of the light sources 310 and the detectors 360.
- each image plane is 12 mm c 6 mm in size, and each light source 310 has lateral dimensions of 1 mm c 1 mm, while each detector 360 has lateral dimensions of 2 mm x 2 mm.
- each detector 360 has lateral dimensions of 2 mm x 2 mm.
- the LiDAR system 300 illustrated in FIG. 3 may afford easier alignments of the optical system as compared to the LiDAR system 200 illustrated in FIG. 2.
- the emission lens 230 may need to be precisely aligned relative to the light sources 210
- the receiving lens 240 may need to be precisely aligned relative to the detectors 260.
- the alignment of the emission lens 230 can be readily checked by turning on the light sources 210 and calibrating the position of the projected light beams.
- the alignment of the receiving lens 240 can be more problematic. For example, if the detectors 260 are placed behind filters or other secondary optics, the imaged spots may not be easily seen.
- both lenses 330 and 340 may be easily aligned relative to the arrays of light sources 310 and detectors 360 by turning on the light sources 310.
- one or more light sources 310a behind the first lens 330 may be fired.
- the emitted light beams may be reflected and received by the corresponding detectors 360b behind the second lens 340.
- one or more lasers 310b behind the second lens 340 may be fired.
- the emitted light beams may be reflected and received by corresponding detectors 360a behind the first lens 330.
- the light sources 310 may be fired sequentially, or two or more light sources 310 may be fired concurrently (e.g., simultaneously).
- EMI shields and light shields may be placed between the first transceiver array behind the first lens 330 and the second transceiver array behind the second lens 340.
- light sources 310 behind both the first lens 330 and the second lens 340 may be fired simultaneously.
- EMI shields and light shields may be placed between adjacent light sources 310 and detectors 360 within a transceiver array to provide electromagnetic and optical isolation.
- FIG. 5 illustrates schematically a scanning LiDAR system 500 according to some embodiments.
- the LiDAR system 500 is similar to the LiDAR system 300 illustrated in FIG. 3, except that the first set of light sources 310a are positioned together on one side of the focal plane of the first lens 330, and the first set of detectors 360a are positioned together on the other side of the focal plane of the first lens 330; similarly, the second set of light sources 310b are positioned together on one side of the focal plane of the second lens 340, and the second set of detectors 360b are positioned together on the other side of the focal plane of the second lens 340.
- the light sources 310 and the detectors 360 may be mounted on a planar printed circuit board (PCB), which may be referred to herein as the optoelectronic board 350.
- PCB planar printed circuit board
- two separate PCB boards may be used - one for the light sources 310a and the detectors 360a positioned behind the first lens 330, and the other one for the light sources 310b and the detectors 360b positioned behind the second lens 340.
- FIG. 6 shows schematically a configuration of the light sources 610 and the detectors 660 according to some embodiments.
- one or more light sources 610 are mounted on one side of a transceiver blade 602; and one or more detectors 660 are mounted on the other side of the transceiver blade 602.
- One or more transceiver blades 602 may be mounted on a PCB 650 to form a transceiver module 600.
- some transceiver blades 602 may have only light sources 610, and some other transceiver blades 602 may have only detectors 660.
- light sources 610 may be placed into a surface mount package, which is in turn mounted on the optoelectronic board 650.
- Detectors 660 may be placed in the same surface mount package, or placed in a separate surface mount package. According to some embodiments, light sources 610 in an array may be mounted at different heights to take into account any lens field curvature. In addition, light sources 610 in an array may be mounted at different angles so that they point substantially toward the center of the lens. Similarly detectors 660 in an array may also be mounted at different heights and/or at different angles.
- the arrangement of light sources and detectors in an array can also have different configurations.
- the light sources 310 may be arranged in alternate rows, separated by alternate rows of detectors 360.
- the light sources 310 and the detectors 360 may be arranged in a checkerboard fashion.
- the light sources 310 may be grouped on one side, and the detectors 360 may be grouped on the other side.
- a hexagonal pattern may also be used.
- the light source and detector arrangement for the first lens 330 may be a flipped or rotated version of the arrangement for the second lens 340.
- FIG. 7 shows an exemplary arrangement according to some embodiments.
- the LiDAR system 700 includes a first transceiver module 600a and a second transceiver module 600b, positioned behind the first lens 330 and the second lens 340, respectively.
- the second transceiver module 600b is rotated by 180 degrees with respect to the first transceiver module 600a.
- a scanning LiDAR system may scan the lens assembly relative to the transceiver array, or scan both the lens assembly and the transceiver array.
- FIG. 8 illustrates a schematic cross-sectional view of a scanning LiDAR system 800 according to some embodiments.
- the LiDAR system 800 may include a fixed base 810, a first platform 820 flexibly attached to the fixed base 810, and a second platform 850 flexibly attached to the fixed base 810.
- the LiDAR system 800 may further include a lens assembly attached to the first platform 820.
- the lens assembly may include a first lens 844 and a second lens 842 mounted in a lens mount 830.
- Each of the first lens 844 and the second lens 842 may include a single lens element, or multiple lens elements as illustrated in FIG. 8.
- the first lens 844 may define a first optical axis in a first direction (e.g., in the direction of the Z- axis) and a first focal plane (e.g., in an X-Y plane).
- the second lens 842 may define a second optical axis substantially parallel to the first optical axis and a second focal plane (e.g., in an X-Y plane).
- the first lens 844 and the second lens 842 may have substantially the same focal length, so that the first focal plane and the second focal plane may be substantially coplanar.
- the LiDAR system 800 may further include transceiver array attached to the second platform 850.
- the transceiver array may include a plurality of light sources 860 and a plurality of detectors 870 mounted on the second platform 850.
- the second platform 850 can be, for example, a printed circuit board (PCB) including electric circuits for driving the one or more light sources 860 and the one or more detectors 870.
- PCB printed circuit board
- a first set of light sources 860a and a first set of detectors 870a may be positioned behind the first lens 844; and a second set of light sources 860b and a second set of detectors 870b may be positioned behind the second lens 842.
- the second platform 850 may be flexibly attached to the fixed base 810 and positioned apart from the first platform 820 in the direction of the first optical axis or the second optical axis (e.g., in the Z direction), such that the light sources 860 and the detectors 870 lie substantially at the first focal plane of the first lens 844 or the second focal plane of the second lens 842.
- the first platform 820 may be flexibly attached to the fixed base 810 via a first set of flexures 822, such that the first platform 820 may be scanned in a first plane (e.g., an X-Y plane) using a first actuator 882 (also referred herein as a driving mechanism).
- the second platform 850 may be flexibly attached to the fixed base 810 via a second set of flexures 852, such that the second platform 850 may be scanned in a second plane (e.g., an X-Y plane) using a second actuator 884.
- Each of the first actuator 882 and the second actuator 884 may comprise a voice coil and a magnet, a piezo motor, or the like.
- the first set of flexures 822 and the second set of flexures 852 may include rod springs that are flexible in one dimension or in two dimensions.
- the rod springs may be made to have slightly different resonance frequencies in two orthogonal dimensions.
- Other types of two-dimensional flexures may also be used.
- the first actuator 882 and the second actuator 884 may be driven at the resonance frequencies of the first set of flexures 822 and the resonance frequencies of the second set of flexures 852, respectively.
- the first actuator 882 and the second actuator 884 may be driven at the resonance frequency of the first set of flexures 822 and the resonance frequency of the second set of flexures 852, respectively, in one dimension only.
- the LiDAR system 800 may further include a controller 890 coupled to the first actuator 882 and the second actuator 884.
- the controller may be configured to scan the first platform 820 and/or the second platform 850.
- the first platform 820 may be scanned along the X axis
- the second platform 850 may be scanned along the Y axis, or vice versa, effectively achieving two-dimensional scanning.
- both the first platform 820 and the second platform 850 may be scanned in two dimensions.
- the scanning pattern may be a raster scan pattern, a Lissajous scan pattern, or the like.
- the motion of the second platform 850 may be substantially opposite to the motion of the first platform 820 at any instant, as illustrated by the arrows in FIG. 8. In this manner, any vibration caused by the motion of the lens assembly may substantially cancel any vibration caused by the motion of the electric-optic assembly to certain degree. Therefore, the LiDAR system 800 may impart a minimal net vibration to an external frame.
- FIG. 9 is a simplified flowchart illustrating a method 900 of operating a LiDAR system according to some embodiments.
- the LiDAR system includes a first lens, a second lens, a first set of light sources, a second set of light sources, a first set of detectors, and a second set of detectors.
- the method 900 includes, at 902, at a first instant, emitting a first set of light pulses using the first set of light sources; and at 904, projecting, using the first lens, the first set of light pulses toward one or more objects.
- the first set of light pulses are reflected by the one or more objects.
- the method 900 further includes, at 906, focusing, using the second lens, the first set of light pulses reflected by the one or more objects onto the second set of detectors; and 908, detecting, using the second set of detectors, the first set of light pulses focused by the second lens.
- the method 900 further includes, at 910, at a second instant subsequent to the first instant, emitting a second set of light pulses using the second set of light sources; and at 912, projecting, using the second lens, the second set of light pulses toward the one or more objects, the second set of light pulses being reflected by the one or more objects.
- the method 900 further includes, at 914, focusing, using the first lens, the second set of light pulses reflected by the one or more objects onto the first set of detectors; and at 916, detecting, using the first set of detectors, the second set of light pulses focused by the first lens.
- FIG. 9 provides a particular method of operating a LiDAR system according to some embodiments of the present invention. Other sequences of steps may also be performed according to alternative embodiments. For example, alternative embodiments of the present invention may perform the steps outlined above in a different order. Moreover, the individual steps illustrated in FIG. 9 may include multiple sub-steps that may be performed in various sequences as appropriate to the individual step. Furthermore, additional steps may be added or removed depending on the particular applications. One of ordinary skill in the art would recognize many variations, modifications, and alternatives.
- FIG. 10 is a simplified flowchart illustrating a method 1000 of aligning a LiDAR system according to some embodiments.
- the LiDAR system includes a first lens, a second lens, a first set of light sources, a second set of light sources, a first set of detectors, and a second set of detectors.
- the method 1000 includes, at 1002, arranging the first set of light sources and the first set of detectors as a first transceiver array positioned substantially at a focal plane of the first lens; and at 1004, arranging the second set of light sources and the second set of detectors as a second transceiver array positioned substantially at a focal plane of the second lens.
- the method 1000 further includes, at 1006, emitting a first set of light beams using the first set of light sources; at 1008, projecting, using the first lens, the first set of light beams toward a screen, thereby forming a first set of light spots on the screen; at 1010, emitting a second set of light beams using the second set of light sources; and at 1012, projecting, using the second lens, the second set of light beams toward the screen, thereby forming a second set of light spots on the screen.
- the method 1000 further includes, at 1014, adjusting a position of the first lens relative to the first transceiver array, and a position of the second lens relative to the second transceiver array, until the first set of light spots and the second set of light spots form a predetermined pattern on the screen, such that each respective detector of the first set of detectors is optically conjugate with a corresponding light source of the second set of light sources, and each respective detector of the second set of detectors is optically conjugate with a corresponding light source of the first set of light sources.
- FIG. 10 provides a particular method of aligning a LiDAR system according to some embodiments of the present invention. Other sequences of steps may also be performed according to alternative embodiments. For example, alternative embodiments of the present invention may perform the steps outlined above in a different order. Moreover, the individual steps illustrated in FIG. 10 may include multiple sub-steps that may be performed in various sequences as appropriate to the individual step. Furthermore, additional steps may be added or removed depending on the particular applications. One of ordinary skill in the art would recognize many variations, modifications, and alternatives.
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- Radar, Positioning & Navigation (AREA)
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Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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EP20749254.7A EP3918367A4 (en) | 2019-01-29 | 2020-01-29 | Lidar system including a transceiver array |
CN202080011372.8A CN113366337B (en) | 2019-01-29 | 2020-01-29 | Lidar system comprising an array of transceivers |
JP2021543382A JP7505789B2 (en) | 2019-01-29 | 2020-01-29 | Lidar system including a transceiver array |
KR1020217026948A KR20210120041A (en) | 2019-01-29 | 2020-01-29 | LiDAR system with transceiver array |
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US201962798407P | 2019-01-29 | 2019-01-29 | |
US62/798,407 | 2019-01-29 | ||
US16/775,166 | 2020-01-28 | ||
US16/775,166 US10935637B2 (en) | 2019-01-29 | 2020-01-28 | Lidar system including a transceiver array |
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WO2020160084A1 true WO2020160084A1 (en) | 2020-08-06 |
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PCT/US2020/015572 WO2020160084A1 (en) | 2019-01-29 | 2020-01-29 | Lidar system including a transceiver array |
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EP (1) | EP3918367A4 (en) |
JP (1) | JP7505789B2 (en) |
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CN (1) | CN113366337B (en) |
WO (1) | WO2020160084A1 (en) |
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US9529079B1 (en) * | 2015-03-26 | 2016-12-27 | Google Inc. | Multiplexed multichannel photodetector |
US11556000B1 (en) | 2019-08-22 | 2023-01-17 | Red Creamery Llc | Distally-actuated scanning mirror |
US11747611B2 (en) | 2020-12-16 | 2023-09-05 | Stmicroelectronics (Research & Development) Limited | Compact line scan mems time of flight system with actuated lens |
DE102021203464A1 (en) | 2021-04-08 | 2022-10-13 | Robert Bosch Gesellschaft mit beschränkter Haftung | Procedure for operating a LiDAR system |
KR20230036930A (en) | 2021-09-08 | 2023-03-15 | 주식회사 엘지에너지솔루션 | Electrode drying system |
DE102022132321A1 (en) | 2022-12-06 | 2024-06-06 | Valeo Detection Systems GmbH | Adaptation method for adapting a total detection field of a LiDAR system of a vehicle depending on a prevailing situation |
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- 2020-01-28 US US16/775,166 patent/US10935637B2/en active Active
- 2020-01-29 EP EP20749254.7A patent/EP3918367A4/en active Pending
- 2020-01-29 WO PCT/US2020/015572 patent/WO2020160084A1/en unknown
- 2020-01-29 CN CN202080011372.8A patent/CN113366337B/en active Active
- 2020-01-29 JP JP2021543382A patent/JP7505789B2/en active Active
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Also Published As
Publication number | Publication date |
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JP2022523493A (en) | 2022-04-25 |
EP3918367A1 (en) | 2021-12-08 |
EP3918367A4 (en) | 2023-01-18 |
CN113366337A (en) | 2021-09-07 |
US20200241113A1 (en) | 2020-07-30 |
US10935637B2 (en) | 2021-03-02 |
CN113366337B (en) | 2022-11-08 |
JP7505789B2 (en) | 2024-06-25 |
KR20210120041A (en) | 2021-10-06 |
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